I. Field of the Invention
The present invention relates to an improved wheel adapter of the type for connecting tandem wheels to the hub of a vehicle axle designed for attachment with a single wheel.
II. Description of the Prior Art
There are a plurality of previously known wheel adapters particularly provided for connecting two wheels to the hub of a vehicle axle which has been designed for attachment with a single wheel. One such wheel adapter is disclosed in U.S. Pat. No. 2,635,012 to Rappaport. These previously known wheel adapters, however, suffer several disadvantages and, as a result, have not enjoyed widespread acceptance or use.
One disadvantage of these previously known wheel adapters is that they are constructed of cast iron and consequently are relatively expensive to construct. Moreover, cast iron is brittle and can fracture upon a sharp impact thus presenting a serious safety hazard.
Another disadvantage of these previously known wheel adapters is that a single set of connectors is employed to simultaneously secure both wheel rims to the hub of the vehicle axle. Consequently, with these previously known wheel adapters removal of the outer wheel will cause a loosening between the adapter and the inner wheel and could cause a loosening of the bolts which hold the inner wheel to the hub.
A still further disadvantage of these previously known wheel adapters is that it is difficult, if not altogether impossible, to accurately coaxially align both wheel rims to each other and with respect to the wheel hub. The inability to accurately align the wheel rims results primarily from the clearance fit between the wheel adapter, the axle hub and the individual wheel rims. Such a clearance fit is necessary to facilitate installation of the wheel rims and the wheel adapter. Misalignment of the wheels disadvatageously results in tire run-out, uneven tire wear and overall excessive wear and deterioration of the wheels.
These previously known wheel adapters are also disadvantageous in that they have been unable to achieve the required rigidity between the wheels necessary to maintain parallelism between the planes of the wheels. This is caused by the slip fit provided between the adapter and the extension bolts and also by reason of the adapter being mounted directly against the inner wheel where there is no provision for accurately locating the adapter with respect to the wheel. This also creates wear between the adapter and the inner wheel and thereby increases the problem of maintaining rigidity and parallelism between the wheels. This lack of parallelism results in wheel wobble, particularly at higher speeds. Moreover, wheel wobble not only causes excessive noise and uneven wheel wear but also results in unstable operation of the vehicle.